Proc Latvian Acad Sci 1998 Supplement; 52 (Sect B) 148-51
A decrease in Cd2+ effects on isolated digestive gland
mitochondria of pectens exposed to the sea water containing CdCl2
Sergei Korotkov, Igor Skulskii, Nina N. Belcheva
Sechenov Institute of Evolutionary Physiology and Biochemistry,
Russian Academy of Sciences, Thorez pr. 44, St. Petersburg 194223,
Russia; korotkov at SK1645.spb.edu
Isolated digestive gland mitochondria (DGM) of two groups of pectens
(Mizuhopecten yessoensis), control and cadmium-treated (kept for 30 days
in sea water containing 0.25 mg/l of CdCl2), were studied. In mitochondria
energised by succinate and malate, state 4 and 3, or 2,4-dinitrophenol
(DNP)-stimulated respiration, and swelling in medium containing K-acetate
and sucrose, were determined. State 4 respiration of DGM isolated from
the control pectens was much more stimulated by 10-50 microM Cd2+ than
that of mitochondria isolated from the cadmium-treated pectens. Cd2+
(10-20 microM) inhibited to the same degree DNP-stimulated respiration
in DGM isolated from both the control and the cadmium-treated pectens.
Inhibition of state 3 respiration in DGM isolated from both control
and cadmium-treated pectens occurred in the presence of 10-20 microM
Cd2+, while only DGM isolated from cadmium-treated pectens had this
response to ADP in experiments with 20-50 microM Cd2+. Energised
mitochondria isolated from control pectens had a lower swelling induced
by 50 mM K-acetate than those isolated from cadmium-treated pectens.
Only DGM isolated from cadmium-treated pectens preserved the swelling
after their preincubation with 24 microM Cd2+. Mitochondria isolated
from control pectens and preincubated with Cd2+ did not swell in the
medium containing 50 mM K-acetate. The results obtained allowed
to conclude that the exposure of pectens to sea water containing
0.25 mg/l of CdCl2 decreased the effect of Cd2+ on isolated digestive
gland mitochondria.
Key words: Cd2+, digestive gland mitochondria, pecten,
mitochondrial respiration, mitochondrial swelling, K-acetate.
---